Don’t do drugs, kids. Especially if you’re female. Women dependent on stimulants like cocaine and methamphetamine appear to have less grey matter, even after they stop using them. Weirdly, men’s brains don’t show this difference.
The brain regions most affected are those involved in reward, emotion and learning – although it isn’t clear yet whether the smaller than average size of these brain areas could be a cause or effect of addiction. Jody Tanabe, at the University of Colorado Hospital in Aurora, hopes these results will help lead to a better understanding of sex differences in substance abuse, and better, more distinct treatments for women.
Tanabe’s team used MRI scans to measure the brain volumes of 59 people previously dependent on stimulants and compared them with people who have never been dependent on these kinds of drugs. On average, the 28 women who had formerly been dependent on a stimulant drug had a smaller volume of grey matter in their prefrontal cortices, temporal lobes, insulae and other regions. This effect was not seen in men.
Shrinking brains
The women who had been addicted also differed in their personalities – on average, they were more impulsive and more reward-driven. We already know that women respond differently to stimulants: they start taking the drugs earlier, use larger quantities and may have more difficulty quitting. It’s possible that this pattern of female addiction could be linked to the brain size difference.
However, it’s unclear whether less grey matter causes female addictive behaviours, or if addiction might shrink these brain regions. “The question of causality is complex. There is evidence for both pre-existing and post-drug changes in brain structure and function,” says Tanabe.

By Lenny Bernstein
Primed by widespread use of prescription opioid pain-killers, heroin addiction and the rate of fatal overdoses have increased rapidly over the past decade, touching parts of society that previously were relatively unscathed, the Centers for Disease Control and Prevention reported Tuesday.
The death rate from overdoses nearly quadrupled to 2.7 per 100,000 people between 2002 and 2013, CDC Director Tom Frieden said during a telephone news conference Tuesday. In 60 percent of those cases, the cause of death was attributed to heroin and at least one other drug, often cocaine, according to Chris Jones, lead author of the report and a member of the Food and Drug Administration's Office of Public Health Strategy and Analysis.
But it is the highly addictive pain-killing opioids, prescribed and sometimes over-prescribed by physicians who are not highly trained in pain management, that concerns officials most, Frieden said.
"A few doses and someone can have a life of addiction, a few too many and someone can die of an overdose," Frieden said. With heroin an estimated five times less expensive than prescription drugs and widely available on the street, people with opioid addictions are turning to the drug in large numbers, he said.
The annual rate of heroin use rose from 1.6 per 1,000 people between 2002 and 2004 to 2.6 per 1,000 between 2011 and 2013, according to the report. That includes a doubling among women, a 114 percent increase for whites and a 109 percent rise among people ages 18 to 25, the report shows.

by Michael Le Page
Humble fungi and a home-brewing kit could soon do what the combined might of the West failed to – halt the thriving poppy industry in Afghanistan, the source of 80 per cent of the world's opium. Genetically engineered yeasts could make it easy to produce opiates such as morphine anywhere, cutting out the international drug smugglers and making such drugs cheap and more readily available.
If home-brew drugs become widespread, it would make the Sisyphean nature of stopping the supply of illegal narcotics even more obvious than it is now. "It would be as disruptive to drug enforcement policy as it would be to crime syndicates," says Tanya Bubela, a public health researcher at the University of Alberta in Edmonton, Canada. "It may force the US to rethink its war on drugs."
A growing number of drugs, scents and flavours once obtainable only from plants can now be made using genetically modified organisms. Researchers want to add opiates to that list because they are part of a family of molecules that may have useful medicinal properties (see box, below). Plant yields of many of these molecules are vanishingly small, and the chemicals are difficult and expensive to make in the lab. Getting yeast to pump them out would be far cheaper.
Yeasts capable of doing this do not exist yet, but none of the researchers that New Scientist spoke to had any doubt that they soon will. "The field is moving much faster than we had previous realised," says John Dueber of the University of California, Berkeley, whose team has just created a yeast that produces the main precursor of opiates. Until recently, Dueber had thought the creation of, say, a morphine-making yeast was 10 years away. He now thinks a low-yielding strain could be made in two or three years.

Andrew Griffin
Evidence that ecigs help people stop smoking real ones is lacking, according to a new analysis.
Electronic cigarettes seem to work for the first month, but there isn’t enough evidence to say that they work for longer periods, researchers said.
"Until such data are available, there are a number of other smoking cessation aids available that have a more robust evidence base supporting their efficacy and safety,” said lead author of the study Riyad al-Leheb, from the University of Toronto.
The analysis looked at four studies of how effective and safe ecigs were, which together had studied 1011 patients.
It found that after one month, using ecigs had significantly improved the amount of people that had stopped smoking. But that effect appeared to have gone at three or six months.
That included studies on people who had used a placebo against those who had used ecigarettes, as well as those who had used nicotine patches.
As well as the apparent lack of permanent help, the analysis found that some studies had found people reported dry cough, throat irritation and shortness of breath. While those adverse effects weren’t any worse among those that used placebo ecigs, they were much less prevalent among those that had used nicotine patches.